Genetic parameter estimates and genotype by environment interaction analyses for early growth traits in grass carp (Ctenopharyngodon idella)

摘要

Despite the importance of grass carp (Ctenopharyngodon idella) in aquaculture worldwide, selective breeding programs for growth traits remain limited. This study aimed to assess the genetic effects and extent of genotype by environment interactions (G x E) for early growth traits in grass carp. Fifty-eight full-sib grass carp families (n = 1704; 20 dams and 15 sires), cultured in two ponds, were reconstructed using molecular parentage analysis. Based on the animal model and restricted maximum likelihood (REML) algorithm, the heritability of standard length (SL), body weight (BW), and condition factor (K) of grass carp at 40 dph (days post-hatch) were calculated as 0.304, 0.307, and 0.150, respectively (P 0.05). Significant genetic and phenotypic correlations were found between SL and BW, 0.838 and 0.958, respectively (P 0.01). The REML likelihood-ratio test between the maternal effects model and animal model showed maternal effects were not significant in early-stage grass carp (P > 0.05). A significant interaction effect was found between family and environment (P 0.01), while Pearson's correlations for SL and BW of grass carp in different ponds were 0.773 and 0.630, respectively. Differential stabilities among families were responded to environments. These results indicate that the early growth traits of grass carp could be improved by exploiting additive genetic effects through selective breeding. Environmental effects and family stability should be taken into account in practical breeding programs.